United Kingdom, Jan. 14 -- Matthew McConaughey believes a successful marriage requires "maintenance".

The 56-year-old actor has been married to Camila Alves since 2012, but Matthew admits that marriage always requires hard work.

During an appearance on the On Purpose podcast, Matthew said: "The honeymoon is all on hope. Honeymoon's only in the perfection stage. It's only in the up in the air."

Matthew acknowledges that the so-called honeymoon period doesn't last forever.

He said: "This is not a popular statement with my wife, but - maybe I'm too practical about love, maybe I'm not romantic enough about it - I don't see how the honeymoon period lasts forever."

Matthew thinks a marriage should be like a "30-watt bulb".

The Oscar-winni...